Thin film deposition by sputtering

Abstract

The deposition of thin films is carried out by a co-sputtering cathode technique particularly suited for deposition of doped thin films on large area substrates. A relatively large planar magnetron sputtering apparatus having a rectangular (picture frame shaped) plasma region is provided to obtain efficient sputtering of the host material. A vacant center area defined by the plasma region is provided for diode sputtering of the dopant. In RF sputtering, co-excitation of the power source is desired to prevent RF mode beating.

We claim: 
     
       1. A sputtering cathode apparatus for deposition of a doped thin film on a substrate which is moved relative to said apparatus, comprising; planar magnetron sputtering means including means defining a frame-shaped plasma area and having a host target material disposed in the magnetron plasma area,   diode sputtering means disposed inside said framed area and out of the plasma sputtering area and comprising a dopant material,   and means for electrically exciting said host target material and dopant material to provide co-deposition of said materials therby forming the doped thin film on the substrate.   
     
     
       2. A sputtering cathode apparatus as set forth in claim 1 wherein said host target material comprises zinc sulfide. 
     
     
       3. A sputtering cathode apparatus as set forth in claim 1 wherein said dopant material comprises manganese. 
     
     
       4. A sputtering cathode apparatus as set forth in claim 1 wherein said planar magnetron sputtering means comprises permanent magnet means. 
     
     
       5. A sputtering cathode apparatus as set forth in claim 1 wherein said means for electrically exciting comprises circuit means for co-exciting the host and dopant materials. 
     
     
       6. A sputtering cathode apparatus as set forth in claim 5 wherein said co-excited respective signals for the host and dopant materials are maintained in phase. 
     
     
       7. A sputtering cathode apparatus as set forth in claim 6 wherein the circuit means comprises an RF oscillator, RF amplifier means coupled from the RF oscillator and impedance matching means coupled from the RF amplifier means to each material. 
     
     
       8. A sputtering cathode apparatus as set forth in claim 7 wherein the RF amplifier means gain is controlled to control percentage to doping in doped thin film. 
     
     
       9. A sputtering cathode apparatus as set forth in claim 1 including means for electrically isolating said planar magnetron sputtering means and said diode sputtering means.